Connecting device



Oct. 10, 1933. c. D. KNOWLTON CONNECTING DEVICE Filed May 15, 1930 35 In the accompanying drawing, 7

, Patented Octr 1 0, 1933,

1.9295533 1-: NN Y H GDEV Cutler Knewlton, Beverly, Mass;, as Signor to Hoague-Sprague COrpoIatiOmCIJynn', Massg a'- corporationof Massachusettsf This invention relates to connecting devices.

It finds a particularly useful place in joining .to each'other such elements as ashaft'anda surroundingmembenfforexample a pulley or a por- 5 tion ofaclutch. w M 3 j An objectof the invention is to so securely hold .-such' -connected rotatable m'emb'ers that their "tendency" to .work loose under sho cks produced by a t n i0PP, n ..anl ei her. changesd? will 2 10 be'm-inimized ,-the' means to eiTect this being simple and readily produced. To attain this object, I provide, in one of the inner and outer members. which are to be joined, preferably the inner, a depression, and in the other or outer member de- ';,'-1'5 pressions shown as angular and separated by an intermediate arcuate'portion of substantial pe-' ripheral extent. Into engagement with the walls of the depressions a unitarysecuring member or key is adapted to be forced, the arcuate portion l providing a space separating the opposedsurfaces of the securing member and of the outer member fromeach other. ,By such a-construction the resistance to the rotative stresses is distributed;

over surfaces between which a perfect bearing '25 may readily be obtainedand which are of such limited areas that the seating-force required for the securing member is not excessive, the central fulcrum surface over which rocking and resultant pounding might occur being entirely omitted. At

1.30 the same time, the manufacturing steps involved in making theconnection are relativelyinexpeni-..45 the rotary-key type, this key 12, for engagement ,.with teeth 14 of the driving member, being arranged to turn in a driven'clutch member. 16 carried by a shaft 18, to which power is'c'ontrollably applied through the clutch. .The clutch-key is "1.150 turnedto engage the teeth, and thus cause rotation of the shaft, by a spring 20, and is disengaged to j free the shaft by a stop 22, which may be moved into the path of a portion of thekey, Obviously,

the shocks imposed upon the means for securing. 5.255 together the shaft 18 and the surrounding clutch tion or depression 24 is formed in the-sh'aftat'its end, this depression being preferablysegmental.

allel -to the axisf'of mam-4r may readily be ground and'ther 'efore produced "in hardened ma"- terial which wouldbe difiicult to mill. In the bore through the hub of the clutch member 16 which shaitdepression 24, andso spaced from each and.

--(01. vest-52.05) a v member 16in starting andfstoppingthe rotation of the former'are considerable; a I

- To associate with the elementsabove described my improved connecting'device, a flattened por- Since the depression extends straight across the shaft, furnishing a plane surface 26 thereon parreceives the" shaft are two V-shaped or angular depressionsf 2 8 having a length at least equal to the other circumferentially of the bore that their walls 30 substantially register, respectively, with the opposite edges of the shaft-surface 26. Between walls 32 of the depressions 28, which lie at right angles to the walls 30 and parallel to the shaftwall 26, there is an unbroken arc 34 of the clutchbore of substantial peripheral extent, the opposite wall furnishing an arc of greater extent. To connect the shaft andclutch member, I furnish a key 36, rectangular in cross-section, having such r a width as to leave some clearance between it and the walls 30, 30, and a thickness giving it a driving fit between the walls 26 and 32, 32. The central portion of the key is separated from the arcuate wall 34 of the clutch-bore. In length, the

key may extend substantially through the depressions 24 and 28, leaving only a suitable clearance at the inner end. .An inclined surface38 upon the inner extremity of the key facilitates its '90 introduction into the depressions. I

In assembling the elements, the outer memberv 16 is placed about theshaft 18 with the depressions 28, 28 opposite the ends of the depression 24. Then the key is inserted and forced: into place; Itwill be seen'that,'because of the separation between the hub-surfaces 32, 32 and their relatively limited lateral dimensions, the contacting surface of the key may-readily be caused to conformsto them, a thing which would be difficult were engagement with the hub sought over the entire opposing surface of the key. As a result of this complete contact, the'relation is a stable one, notlikely to' b'e disturbed by driving forces even when changes are sudden; and extreme.

These forces are received upon the surfaces 32, 105 I 32 considerably removed from the radius which bisects the key, at which point the resistance offered by the contact between the key and hub'i and opposing relative rotationwould be a minimum, and thus the advantage of a considerable 1 -1 0 resisting leverage obtained. To put this in another way, there being no contact between the central area of the key and the arcuate surface 34 of the hub, the fulcrum about which variations in the driving or resisting forces might cause a rocking action to be set up is absent, and the tendency of the connection to work loose is greatly reduced. At the same time, the limited area of contact between the key and hub lessens the force required to seat the former and conse-:

quently reduces the danger of bursting the hub. When the outer member is to be applied to an arbor, the arcuate wall 34 contacting therewith gives more perfect engagement than would be the case were this portion of the hub cut away.

The single key presents an extended bearing area,

of the United States is:

V l. The combination with inner and outer rotatable members, one being provided with a depression and the other with depressions separatedby an intermediate arcuate portion of substantial. peripheral extent, said depressions and arcuate portion extending along the opposed surfaces of the members substantially parallel to the axis of rotation, of a unitary securing member adapted to be forced into engagement with the walls of the depressions, the arcuate portion providing a space separating the opposed surfaces of the securing member and the outer member from each other.

2. The combination with a shaft provided with a segmental depression and a member having an opening to receive the shaft and depressions separated by arcuate walls of the shaft-receiving opening in both directions c'ircumferentially of said opening, of a key consisting of a unitary member having a driving fit in the depressions of both the shaft and member and securing the two together, the outer face of said key between the depressions in the member being spaced from the opposed arcuate wall.

3. In 'combination a member provided with a bore in the cylindrical wall of which are two V-depressions spaced from each other by arcuate wallsof unequal'extent, a shaft lying within the opening and having, upon its periphery a. plane surface opposite the arcuate wall of lesser extent and with its longitudinal edges substantially-reg:-

the shaft, said key being spaced from the lesser arcuate wall of the bore.

CUTLER D. KNOWLTON'. 

